1. Field of the Invention
The present invention relates to a fan structure in which the shaft rod is prevented from being deflected during the assembling or transfer process of the fan so that the shaft rod will not be stuck with the bearing.
2. Description of the Related Art
A conventional thermal module is generally composed of multiple heat dissipation units assembled with each other, including heat sink, heat pipe and cooling fan. In heat dissipation process, the heat sink can increase the heat dissipation area and the heat pipe can increase the heat transfer efficiency. As the electronic device operates at higher and higher speed, the electronic components inside the electronic device for operation work generate high heat. In the case that the heat still cannot be efficiently dissipated by means of both the heat sink and the heat pipe, it is necessary to use a cooling fan to forcedly dissipate the heat so as to lower the temperature of the electronic components and avoid burnout of the electronic components due to overheating.
The cooling fan is composed of a frame body, a rotor and a stator. A bearing cup perpendicularly extends from the frame body. A bearing is disposed in the bearing cup. The rotor includes a hub and a shaft rod. The hub has multiple blades outward extending from the hub. One end of the shaft rod is connected with the hub, while the other end of the shaft rod is rotatably connected with bearing. The stator includes multiple stacked silicon steel sheets and multiple windings wound around the silicon steel sheets. The bearing and the shaft rod are rotatably assembled with each other in a loose fit manner. In operation of the cooling fan, the shaft rod is rotated relative to the bearing. A small gap exists between the shaft rod and the bearing. In general, a lubricant is filled in the gap to reduce frictional wear between the shaft rod and the bearing. Due to the gap, during the transfer or assembling process of the cooling fan, the shaft rod is likely to deflect due to vibration. As a result, the blades tend to be stuck with the frame body and the shaft rod tends to be stuck with the bearing. Under such circumstance, the cooling will damage and fail.